The role of ceramidase in murine ovarian granulosa cell death / 대한산부인과학회잡지

OBJECTIVE: One of the models we study is the ovarian granulosa cell (GC), a somatic cell lineage that is critically important for maintenance of the female germ line and many endocrine functions of the ovaries. The objective of this study is to clarify the significance of ceramide and the role of ceramide metabolism in dictating the fate of cells exposed to stress. METHODS: We first treated GC with a C8-ceramide analog or an amine derivative of ceramide that cannot be metabolized by ceramidase (C8-ceramine). Northern blot analysis was performed to evaluate mRNA of acid ceramidease expression regualted by gonadotropin and in situ hybridization was done to identify the mRNA expression of acid ceramidase in ovaries. RESULTS: After 6 hours, C8-ceramide (50 micro M) triggered apoptosis in only 28 +/- 6% of the cells, whereas C8-ceramine (50 micro M) induced apoptosis in all cells (LD50=1 micro M). These data suggested that ceramidase activity is a critical determinant of GC survival. In situ hybridization showed that mRNA of acid ceramidase was highly expressed in GC in growing follicle. mRNA of acid ceramidase was expressed abundantly in granulosa cells and ovaries and its expression was significantly increased by gonadotropin in granulosa cells in in situ hybridization. Forty two hour after gonadotropin treatment, mRNA expression of acid ceramidase in granulosa cells was two fold increased cells comparing with no treatment control in northern blot analysis (P<0.05). In copora lutea, elevated mRNA expression of acid ceramidase was decreased. CONCLUSION: We concluded that GC possess inherently high levels of ceramidase activity, and that ceramidase has important for metabolizing ceramind to maintain GC survival in the ovary.

Crystalloid Resuscitation in Experimental Hemorrhagic Shock in Dogs / 대한마취과학회지

Although crystalloid solutions such as Ringer's lactate have become the standard for initial volume replacement after hemorrhage, it is controversy whether this fluid alone restores and maintains the depressed physiologic function after severe hemorrhage. Six anesthetized dogs were bled(35ml/kg) and resuscitated with Ringers lactate solution (100 ml/kg). Physiologic variables are measured initialy, after hemorrhage, after resucitation. Compared with initial value, after resuscitation data show marked reduction in hemoglobin, oxygen carrying capacity, vascular resistance, and electrolyte. But cardiac output and blood gas analysis data was not changed. Prothrombin time and partial thromboplastin time was prolongated. From this study crystalloid resuscitation in severe hemorrhagic shock restore cardiac output and perfusion, but fail to maintain adequate oxygen carrying capacity.